RIG-I and MDA5 fRIP during KSHV lytic reactivation

The RIG-I like receptors (RLRs) RIG-I and MDA5 are cytosolic RNA helicases best characterized as restriction factors for RNA viruses. However, evidence suggests RLRs participate in innate immune recognition of other pathogens, including DNA viruses. Kaposi's sarcoma-associated herpesvirus (KSHV) is a human gammaherpesvirus and the etiological agent of Kaposi's sarcoma and primary effusion lymphoma (PEL). We demonstrate that RIG-I and MDA5 restrict KSHV lytic reactivation in PEL. By performing fRIP-Seq, we define the in vivo RLR substrates and demonstrate that RIG-I and MDA5-mediated restriction is facilitated exclusively by the recognition of host-derived RNAs. Overall design: Inducible F-RIG-I and F-MDA5 BC-3 cells, as well as control BC-3 cells were treated with 1 µg/ml of doxycycline, 20ng/ml tetradecanoyl phorbol acetate and 0.1 mM sodium butyrate for 48 h. Flag fRIP was performed and RNA was submitted for high throughput sequencing.